Earlier this week, the LA Times published a recipe that essentially contained that instruction. Fortunately, it doesn't require you to directly measure and add such a small quantity (about 13 microliters), and instead uses an indirect method: extract 1/2 teaspoon of a mixture of 1 cup water and 1/4 teaspoon yeast, and add that to the flour. That's an instruction that will cause convulsions in anyone who normally uses the metric system in the kitchen. (Of course, the preferred way to measure such a small quantity of a granular substance is by mass, not by volume)